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United States Patent | 6,229,778 |
Ikegame ,   et al. | May 8, 2001 |
An information recording reproducing apparatus for recording and/or reproducing informations on and/or from an optical recording medium. The apparatus comprises a light source, at least two objective lenses corresponding to at least two kinds of optical recording media having different thicknesses of a protective layer, respectively, a rotatable holder for supporting these objective lenses, magnetically activatable selection elements for these objective lenses in accordance with the optical recording medium, the light of the light source being illuminated on the optical recording medium through the objective lens selected by the magnetically activatable selection elements, thereby performing recording and/or reproducing of the information.
Inventors: | Ikegame; Tetsuo (Hachioji, JP); Nakano; Osamu (Hachioji, JP) |
Assignee: | Olympus Optical Co., Ltd. (Tokyo, JP) |
Appl. No.: | 555793 |
Filed: | November 9, 1995 |
Nov 10, 1994[JP] | 6-276491 |
Current U.S. Class: | 369/53.22; 369/53.28 |
Intern'l Class: | G11B 007/085 |
Field of Search: | 369/44.12,44.23-44.24,44.32,54,58,112 |
4956833 | Sep., 1990 | Kokado et al. | 369/112. |
5216649 | Jun., 1993 | Koike et al. | 369/44. |
5235581 | Aug., 1993 | Miyagawa et al. | 369/44. |
5321678 | Jun., 1994 | Takishima et al. | 369/44. |
5408455 | Apr., 1995 | Takishima | 369/44. |
5729510 | Mar., 1998 | Kasahara et al. | 369/44. |
5930214 | Jul., 1999 | Kasahara et al. | 369/58. |
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Shigeo Kubota, et al., "An analysis of Eye Diagram Phase Jitter in Optical Disk Systems IV, The Influence of Spherical Aberration Caused by Disk Thickness Error," Jan. 14, 1985, Optics 14, pp. 219-221, with three page English translation of pertinent parts. Patent Abstracts of Japan, vol. 001, No. 104 (E-044), Sep. 14, 1977, and JP-A-52 037404 (MEI Co. Ltd.), Mar. 23, 1977. Patent Abstracts of Japan, vol. 95, No. 5, Jun. 30, 1995, JP 07037259A (Ricoh Co. Ltd), Feb. 7, 1995. |